A study of the genetics of myopia in collaboration with Dr. Dwight Stambolian is ongoing. Dr. Stambolian is continuing to collect pedigrees with myopia from several populations and has begun a linkage study of this disorder. We have conducted power analyses of the existing pedigrees to determine if they will have adequate power to detect major loci contributing to the susceptibility to myopia and to determine how many more such pedigrees may be necessary to have adequate power to detect genes of moderate effect or major loci in the presence of heterogeneity. This ongoing data collection process has been extended to 4 populations. Dr. Bailey-Wilson also advises Dr. Stambolian and the other data collection sites on the type of family structures that will maximize power for linkage studies. In this fiscal year, a paper was published showing no evidence in our Amish and Ashkenazi Jewish families for linkage to two candidate regions on chromosomes 12 and 18 that have been implicated by previous linkage studies as possibly harboring loci for susceptibility to high (extreme) myopia. In addition, a set of completely sampled families from the Ashkenazi Jewish and Amish populations have been genotyped for a genome wide screen at the Center for Inherited Disease Research and have been analyzed in Dr. Bailey-Wilson?s section. Evidence for linkage to chromosome 22 has been published for the Ashkenazi Jewish families and a manuscript is in preparation presenting the Amish analyses. Analyses of refractive error is ongoing in these families. Additional families have been genotyped for a genome wide scan and will be analyzed in the next fiscal year. In addition, a dense map of SNP markers is being genotyped in the Ashkenazi families to follow up the chromosome 22 linkage.